Distributor devices



March 1956 G. N. BEDDOES ETAL 3,241,532

DISTRIBUTOR DEVICES Filed April 24, 1964 2 Sheets-Sheet 1 "a 1011 9a, 8a 6a 12 SUPPLY VOLTS PULSE P CONTKOL: GENERATOR VOL r5 L H 5 II 8 II 5 H 5 v rv g-v gv E G/NE I lnvenlors GMBea does CF Lloyd March 1966 G. N. BEDDOES ETAL 3,

DISTRIBUTOR DEVICES Filed April 24, 1964 2 Sheets-Sheet 2 I nvenlors G M Beds/02.5 c. F. Lloyd By Z Mtomeys United States Patent 3,241,532 DISTRIBUTUR DEVIQES Gerald Norman Beddoes and Carl Frederick Lloyd, both of I .eamington Spa, England, assignors to Associated Engineering Limited, Warwickshire, England, a British company Filed Apr. 24, 1964, Ser. No. 362,384 Claims priority, application Great Britain, May 1, 1963,

17,1'76/ 63 4 Claims. (ill. 12332) The present invention relates to distributor devices particularly for use in fuel injection systems, and also to fuel injection systems incorporating such distributor devices.

It is an object of the invention to provide a distributor device suitable for use in fuel injection systems employing a plurality of electromagnetically operated fuel injection valves and which operates to feed pulses to energise the injection valves in turn so as to open said valves to pass fuel to the engine.

It is a further object of the invention to provide a distributor device in the form of a high speed switch.

From one aspect of the invention provides a distributor device, particularly for fuel injection systems, comprising a plurality of sets of contacts and a rotatable cam member for operating said sets of contacts in succession, wherein each set of contacts includes a first pair of contacts closed by the cam member and a second pair of contacts which are closed only after the first pair of contacts has been closed.

The invention also consists in a fuel injection system for internal combustion engines, comprising plural electromagnetically operated fuel injection valves and a control circuit producing electrical pulses for energising said valves in turn to open said valves to pass fuel to an engine, and including a distributor device having a plurality of sets of contacts which are closed in succession by a cam member driven in synchronization with the operation of the engine, wherein each set of contacts comprises a first pair of contacts initially closed by the cam member and which serve to feed an out-put pulse from the control circuit to a fuel injection valve to open said valve and a second pair of contacts which are closed after the first pair of contacts are closed and which serve to trigger the control circuit to produce the said output pulse.

Preferably the contacts of each set are arranged in a stack and are attached to spring blades which are separated by members of insulating material.

According to a feature of the invention a tappet is located opposite each set of contacts and is engaged by the cam member to cause the closure of the contacts of each set in succession.

According to one form of the invention, the cam is arranged on the side of a rotatable shaft and the contacts are disposed in axial planes around the shaft. According to an alternative form of the invention, the cam is arranged on the end face of a rotatable shaft and the contacts are disposed in radial planes, and may be located beyond the end of the shaft. 1

In order that the invention may be more fully understood, some embodiments thereof will now be described, by way of example, with reference to the accompanying drawings, in which:

FIGURES 1a and 1b are respectively a side sectional view and a plan view with the cover removed of one embodiment of distributor device according to this invention,

FIGURES 2a and 2b are respectively a side sectional view and a plan view also partly in section, of a further embodiment of distributor device, and

FIGURE 3 is. a simplified circuit diagram of a fuel injection system according to this invention.

Referring to FIGURES 1a and 1b, the distributor device comprises a base member 1 on which is mounted a sup port member 2 which serves to carry four sets of contacts C. The contacts of each set are operated by a cam 3 formed on a shaft 4 mounted in bearings 5. Where the distributor device is used for triggering a pulse generator and for distributing its output pulses to energise electromagnetic fuel injection valves of a fuel injection system for an internal combustion engine, this shaft is driven from the engine so that operation of the contacts of each set is correctly phased in relation to operation of the engine.

Arranged radially about the shaft are a series of tappets 6 sliding in guides 7 in the support member 2. The four contacts 8, 9, 10 and 11 of each set are respectively attached to the spring blades 8a, 9a, 10a and 11a mounted between blocks of insulating material 12. A flexible member 13 of insulating material is also positioned between the two pairs of contacts of each set. Holes 14 are provided through the base member for connecting leads to the ends of the spring blades remote from the contacts. The assembly is enclosed within the cover 15.

In operation, when the tappets 6 are lifted in succession by rotation of the cam 3 with the shaft 4, the head 6a of each tappet deflects the associated blade 3a closing the pair of contacts 8 and 9. Further movement of the tappet deflects these contacts, carrying with them the blade 10a which in turn causes the pair of contacts 10' and 11 to close.

As applied to a fuel injection system, as will be hereinafter explained with reference to FIGURE 3, the electrical connections to the contacts are so arranged that the closing of each pair of contacts 10 and 11 triggers the pulse generator and the resulting output pulse from the pulse generator is fed via the associated pair of contacts 8 and 9 to energise the appropriate electromagnetic fuel injection valve and cause it to open to pass fuel to the engine. For this purpose the contacts 8 and 9 are capable of carrying a high current whilst the contacts 10 and 11 need only be capable of carrying a low current.

The dimensions of the tappets 6 and their tappet guides 7, as well as the dimensions of the cam 3, are so arranged that when the sets of contacts open, the head of each tappet comes to rest on the guide, the other end being held .a small distance clear of the cam. This allows air to cool the contact .area of the tappet and minimises wear.

If required, a further spring blade can be incorporated immediately adjacent to each blade 8a to provide the necessary spring stiffness to help return the associated tappet to its rest position.

The spring blades 9a and 11a are preformed so that on assembly they are loaded on the projections 12w of the insulating members between them. This ensures that when the adjacent blades come into contact, a contact load is built up immediately instead of a gradual build up as the blade is deflected.

FIGURES 2a and 2b show .a further embodiment of distributor device wherein corresponding parts have been given the same reference numerals. In this embodiment the cam 3 is arranged on the end face of the rotatable shaft 4. A thrust bearing 5a is arranged between the end of the shaft and a steel plate 2 which serves to support the sets of contacts C and is also formed with the guides 7 for the tappets 6. The contacts of each set 8, 9, 10 and 11 mounted on their spring blades 8a, "911, 10a and 11a are supported from the steel plate and are separated by members 12 of insulating material which are in the form of rings common to all of the sets of contacts. A member 13 of flexible insulating material is also arranged between the two pairs of contacts of each set.

Arranged around the periphery of the assembly is a sheet 16 of flexible insulating material carrying printed conductors by means of which electrical connections may be made to the contact sets, and connecting tags 17 to the conductors on the printed circuit extend through the upper cover member 15a of the device. A side cover 15b is clamped between this upper cover member and the base 1 of the device.

Whilst in both of the embodiments described the distributor has been shown as comprising four sets of contacts, it will be understood that such devices may be constructed with any desired number of sets of contacts. Thus six sets of contacts would be provided where the device is to be used for distributing pulses to fuel injection valves for a six-cylinder engine.

FIGURE 3 illustrates a fuel injection system for a four cylinder internal combustion engine incorporating a distributor construction according to the present invention. The fuel injection system incorporates tour electromagnetically operated fuel injection valves V, having solenoids S which are energised to open the valves to inject fuel into the engine E. The injection valves V may be mounted in the inlet manifold of the engine. The solenoids are energised by means of a control circuit or pulse generator P which is triggered to produce the output pulses. The pulse generator is fed with supply voltages and also with control voltages which adjust the duration of the output pulses in accordance with engine operating conditions and the system may operate generally in the manner described in copending application No. 284,- 031, filed May 29, 1963, to the same assignees. The four sets of distributor contacts 8, 9, and 11 are shown as connected to the circuit. The contacts of each set are closed in succession by the cam member 3 mounted on the shaft 4 driven in synchronism with the operation of the engine. The first pair of contacts 8, 9 of each set initially closed by the cam member 3 serves (when the pulse generator P has been triggered) to feed the output pulse from the pulse generator to the energising solenoid S of the fuel injection valve V associated with that set of contacts so as to open the valve to allow fuel to flow to the engine. The second pair of contacts 10 and 11 of each set are only closed after the first pair of contacts has become closed and serve to trigger the pulse generator P to produce the aforementioned output pulse which is fed to the associated fuel injection valve.

The advantages of the distributing devices according to this invention are:

(a) The correct phasing of the trigger and distributor contacts is inherent in the design in that the pulse generator cannot be triggered before the distributor contacts have closed. The phase angle between the making of the distributor contacts and triggering is held to a small value thus making available the maximum time for the pulse.

(b) Since all of the contacts are operated by a single cam, phasing of one injection point to the next is controlled by the angular positioning of the tappets, which can be held as accurately as required.

(c) All electrical connections are made to stationary parts of the unit thereby obviating the danger of fatigue in connections etc.

(d) The moving parts are small and light and the unit can be made to function at high speeds quite easily.

(e) The number of parts, especially those working or wearing is small.

(f) The overall dimensions are small. (g) The camshaft can be rotated in either direction.

Whilst particular embodiments have been described it will be understood that various modifications may be made without departing from the scope of this invention.

It will be understood that the distributor devices may be used for other purposes besides its use in fuel injection systems. Thus since the distributor devices according to the present invention are capable of rotating at high speeds, of the order of 4,000 r.p.m. and higher, the devices con stitute high speed rotary switches which may be used in telemetry and for other applications.

We claim:

1. A fuel injection system for internal combustion engines, comprising plural electromagnetically operated fuel injection valves and a control circuit producing electrical pulses for energising said valves in turn to open said valves to pass fuel to an engine and including a distributor device 'having a plurality of sets of cont-acts which are closed in succession by a cam member driven in synchronization with the operation of the engine, wherein each set of contacts comprises a first pair of contacts initially closed by the cam member and which serve to feed an output pulse from the control circuit to a fuel injection valve to open said valve and a second pair of contacts which are closed after the first pair of contacts are closed and which serve to trigger the control circuit to produce the said output pulse.

2. Apparatus as claimed in claim 1, including a tappet located opposite each set of contacts and which is engaged by the cam member to cause the closure of the contacts of each set in succession.

3. A fuel injection system for internal combustion engines, comprising plural electromagnetically operated fuel injection valves and a control circuit producing electrical pulses for energising said valves in turn to open said valves to pass fuel to an engine and including a distributor device having a plurality of setsof stashed contacts which are closed in succession by a cam member mounted on a shaft driven in synchronization with the operation of the engine, wherein each set of contacts comprises a first pair of high current contacts initially closed by the cam memher and which serve to feed an output pulse from the control circuit to a fuel injection valve to open said valve and a second pair of low current contacts which are closed after the first pair of contacts are closed and which serve to trigger the control circuit to produce the said output pulse.

4. A system as claimed in claim 3, including a printed circuit arranged around the sets of cont-acts and carrying conductors for making electrical connection to the contacts.

' References Cited by the Examiner UNITED STATES PATENTS 864,077 8/ 1907 Butler et al ZOO-27 2,892,047 6/1959 Smith ZOO-30 2,990,459 6/ 1961 Stanbro et a1 20027 3,011,486 12/1961 Pribble 123-32 3,078,405 2/1963 Tice 20027 FOREIGN PATENTS 894,284 3/ 1944 France. 1,213,758 11/1959 France.

539,238 9/1941 Great Britain.

MARK NEWMAN, Primary Examiner. RICHARD BL WILKINSON, Examiner. 

1. A FUEL INJECTION SYSTEM FOR INTERNAL COMBUSTION ENGINES, COMPRISING PLURAL ELECTROMAGNETICALLY OPERATED FUEL INJECTION VALVES AND A CONTROL CIRCUIT PRODUCING ELECTRICAL PULSES FOR ENERGISING SAID VALVES IN TURN TO OPEN SAID VALVES TO PASS FUEL TO AN ENGINE AND INCLUDING A DISTRIBUTOR DEVICE HAVING A PLURALITY OF SETS OF CONTACTS WHICH ARE CLOSED IN SUCCESSION BY A CAM MEMBER DRIVEN IN SYNCHRONIZATION WITH THE OPERATION OF THE ENGINE, WHEREIN EACH SET OF CONTACTS COMPRISES A FIRST PAIR OF CONTACTS INITIALLY CLOSED BY THE CAM MEMBER AND WHICH SERVE TO FEED AN OUTPUT PULSE FROM THE CONTROL CIRCUIT TO A FUEL INJECTION VALVE TO OPEN SAID VALVE AND A SECOND PAIR OF CONTACTS WHICH ARE CLOSED AFTER THE FIRST PAIR OF CONTACTS ARE CLOSED AND WHICH SERVE TO TRIGGER THE CONTROL CIRCUIT TO PRODUCE THE SAID OUTPUT PULSE. 